Brush plate assembly



Aug. 22, 1933. H J H M ET AL BRUSH PLATE ASSEMBLY Filed Dec. 27, 1930- 5Sheets-Sheet l Mentor HERBERT J. GRAHAM LEWIS A. DARLING 1933- I H. J.GRAHAM El AL 1,923,864

BRUSH PLATE AS SSSS LY Filed Dec. 27, 1930 3 Sheets-Sheet 2 lhdentorHERBERT J- GR AM LEWIS Roam. l I

' iior'rzegl.

Aug. 22, 1933. R H M r AL 1,923,864

BRUSH PLATE ASSEMBLY Filed Dec. 27, 1930 3 Sheets-Sheet 3 [MG/7&0?HERBERT J. GRAHAM LEWIS A. DARIJNG 3 1 I I flifiorneyi Patented Aug. 22,1933 UNITED STATES Piraeus?!orriosi Bnusn i delphia, Pa assignors toElectric ServiceSupplies Company, Philadelphia, Pa., ,a Corpora;

tion of Pennsylvania Application December 27, 1930 Serial No. 505,084

11 Claims. (01. 171-324) This invention relates generally to electricgenerators and the like and more particularly to improvements in theconstruction of the rigging for supporting the commutator brush holdersand their associated parts. I

Heretoiore and prior to this invention considerable difficulty has beenencountered due to leaking or stray currents in direct currentgenerators, this condition being especially serious in the case ofgenerators employed for the head lighting of locomotives, train control,train sig- I181 systems and the like. One cause of this leakage or straycurrent is due to the faulty design or the commutator brush rigging ormounting, various attempts having been made from time to time to curethis fault by suitably insulating the brush holders from theirsupporting structure. Because of the relatively severe vibration towhich the brush rigging is ordinarily subjected during the operation ofthe generator, the usual devices resorted to for supporting the brushholders in insulated relation with respect to each other and to thegenerator housing have failed. It is to overcome these difficulties thatthe present invention has been developed.

Among the. principal objects of the'present invention is, to provide abrush plate assembly or rigging which is adapted to supportthecommutator-brush holders with sufficient rigidity to overcomevibration when the generator is in use; to provide a supportingstructure for the brush holders by virtue of which the current leakagefrom the brush holders to the supporting framework of the generator isdecreased to a veritable minimum, if not entirely eliminated; to providean insulating plate upon which the brush holders are mounted and whichis reinforced-in such manner as to withstand the injurious effects ofvibration and temperature variations during the operation of thegenerator; to provide a brush plate assembly which is capableotsupporting two sets of commutator brushes respectively adapted foroperative coaction with the separate commutators of a two-voltagegenerator, the assembly being so designed .as to effectively insureagainst direct metallic contact between the brush sets as well asbetween each of the latter and thegenerator housing; and to generallyprovide a structurally simple, inexpensive and durable brush riggingwhich may be readiiy attached to or detached from the generator housingas a compact, self-contained unit without necessitating the separateremoval of the brush holders and their associated parts.

Other objects andadva-ntag-es of the invention will be apparent morefully hereinafter.

'The invention consists substantially in the combination, construction,location and relative arrangement of parts, all as will-appear in moreor less detail hereinafter, as shown in the ac 5 companying drawings andas finally pointed out in the appended claims. In the accompanyingdrawings the invention has been illustratedin conjunction with agenerator forming part of a turbo-generator unit, it being understood,or course, that the invention is not intended to be limited solely tothe type of unit shown but may be employed in connection with othertypes of direct current generators as well as direct cur rent motors. Inthe said draWingst- Figure l is an elevational View of a turbogeneratorunit, the generator unit or" which the present invention forms a partbeing partially shown in section; I q 7 Figures 2 and 3 are verticalcross-sectional views taken on the lines'22 and"3-3, respectively, ofFigure 1';

Figure 4 is a vertical cross-sectional view of the brush holdersupporting unit per se; Figure 5 is an elevational view of the cuterface of the unit shown in Figure 4 and Figure 6 is arr-enlargedviewtaken on the line 6-6 of Figure 2 and showing "a detail or theinvention. 7

Referring now to the drawings 'andmore particularly to Figure 1 thereof,it'will be observed that the invention has been shown for purposes ofillustration as incorporated in the generator 1-0 of a turbo-generatorThis generator 10 embodies the usual housing frame 11 within vwhich aresuitably arranged the usual armature and "field magnets. In theparticular instance shown the generator armature embodies two sets ofcurrent generating coils for generating separate currents of differentvoltage. Op erativelyassocia-ted with the armature are a pair ofcommutators 12 and 13 commonlysupported upon the free end of thegeneratorshaft 14, one commutator being provided for each set of current generating coils- Extending across the outer render the annularhousing frame 11 is the rigging for supporting the commutator brushesfin operativerela-tion withrespect to the commutators 12 and 13, thisrigging beingdesignated generally by the refer-7 ence numeral 1-5. Asmost clearly appears in Figure 4 this rigging 15 includes asubstantially fiat plate :or disc 16 of insulating material. V Thisplate 16 is prererablyof circular rorm'jarid 11.0

is centrally apertured as at 17 to permit the same to be slipped axiallyover the commutators 12 and 13.

Secured to the peripheral edge or margin of the insulating plate 16 andprojecting axially forwardly of the plane thereof is an annular member18 of metal. This metallic annulus 18 is provided in the inner edgethereof with a circumferentially extending shoulder 19 to provide anannular seat or depression within which the insulating plate 16 isreceived. Extending radially inwardly of the metal reinforcing ring 18are a plurality of circumferentially spaced projections 20 against theinner surfaces of which the plate 16 is adapted to be disposed inflatwise relation. The plate 16 and these radially extending projections20 are commonly apertured to receive the securing elements 21, theselatter being the form of tubular rivets for firmlyand permanentlysecuring the plate 16 to the metal ring 18 in the relation shown.

The ring 18 is provided intermediate the opposite edges thereof with acircumferentially extending flange 22 which is adapted to be seatedwithin a suitable annular seat or depression 23 formed in the outer endof the housing frame 11 of the generator. Formed integrally with theannulus 18 are a plurality of angularly shaped arms 24 the free ends 25of which are disposed in a plane substantially paralleling and axiallyoffset from that of the insulating plate 16. In the particular instanceshown (see Figure 5) three arms 24 are employed, the free ends 25thereof being each provided with an interiorly threaded aperture 26.

Adapted to be supported upon the arms 24 in spaced relation with respectto the insulating slate 16 is an auxiliary plate 27, also of insulatingmaterial. As appears most clearly in Figure 5 the plate 27 is ofsubstantially triangular shape having apertures 28 formed in the severalcorners thereof through which suitable screws 29 may be inserted forthreaded engagement with the tapped holes 26 respectively provided inthe arms 24 of the metallic reinforcing ring 18. It will be observedthat the auxiliary plate 27 is arcuately cut out as at 30 to provide asuitable clearance for the outer armature 13. It will be understood thatwhen the plate 27 is mounted in position upon the ring 18 as justdescribed it is disposed in a plane substantially parallel to butaxially offset from that of the insulating plate 16.,

These insulating plates 16 and 27 respectively constitute the supportsfor the brush holders which are operatively associated with thecommutators 12 and 13. It will be observed that the commutator 12 isprovided with four current collecting brushes 30, which latter areslidably retained by suitable brush holders 31 31 31, and 31respectively mounted upon the insulating plate16., The commutator 13, onthe other hand;,is in the present instance provided with only twocurrent collecting brushes 32 which are slidably retained by thebrushholders 33 and 33 mounted upon the insulating plate 27'. The brushholders are all identical in construction and in each instance thebrushes respectively associated therewith are radially urged toward thecommutators under the influence of spiral springs 34 respectively coiledabout the screw studs 35. In accordance with V the common practice thebrushes are electrically connected to their respective holders byflexible conductors (not shown).

As appears quite clearly in Figures 2 and 3 the brush holders 31 31*, 31and 31 are selar rivets 36 are projected.

In substantially similar fashion, the brush holders 33 and 33 aresecurely mounted upon the auxiliary plate 27 by means of the tubularrivets 38. One of these rivets, designated as 38', is preferablyinteriorly threaded as at 39 for threadedly receiving the end of a splitpin 40. The free end of this pin is adapted to be axially inserted intothe bore of the tubular rivet 36' when the plate 2'7 is positioned uponthe annular ring 18 whereby to not only constitute a supporting elementtherefor which is auxiliary to the supporting arms 24 of the metalreinforcing ring but to also provide anefiective electrical connectionbetween the brush holder 33 which cooperates with the commutator 13 andthe brush holder 31 which cooperates with the commutator 12. It will beunderstood that in practice the positive brush holders 31 and 31 (32volt) for the commutator 12 are connected together by the conductor 41which latter is in turn connected to the positive 32 volt terminal ofthe generator by the conductor 42 which is threaded through a suitableaperture .43 provided in the plate 16. The negative brush holders 31 and31 (32 Volt) for the commutator 12 are connected together by theconductor 44 and through the pin 40 to the negative brush holder whichrelates primarily to the plate assembly a or rigging for supporting thebrush holders in operative position and in insulated relationship withrespect to the associated parts of the generator. Suitably arranged tocover the rigging and the several parts associated therewith is aprotective cover or door 4'7.

While in the present instance we have chosen to illustrate the inventionas incorporated in a rigging for supporting a dual set of brush holders,it is to be understood that in those installations where only one set ofbrushes is employed, the auxiliary plate 27 will be dispensed with andthe metal reinforcing ring 18 will be formed without the radiallyextending arms 24. It will of course also be apparent that the annularmetallic ring 18 may be applied to the peripheral or marginal edge ofthe insulating plate 16 by other means than that herein shown anddescribed without departing from the essential spirit of theinvention-namely, the provision of a unitary'brush plate assembly theprincipal element of which includes a support of insulating materialwhich is reinforced in its marginal edge by a metallic annulus. We havefound by experience that a rigging constructed in accordance with andembodying the principles of Obviously by changing the number ourinvention not only efiectively insures against the leakage of currentfrom the brush holders to the generator frame or housing but also iscapable of withstanding the relatively severe .vibration to whichgenerators are ordinarily subjected when used particularly in therailway field. Another important feature of our present inventionresides in the fact that the rigging is in the form of a self-containedunitary assembly capable of being readily secured in or removed fromoperative position merely by the removal of a few screws and withoutnecessitating the disorganization or removal of the several partscarried thereby.

It will be understood that the invention is susceptible of variouschanges and modifications without departing from the real spirit orprinciples thereof and it is accordingly intended to claim the samebroadly as well as specifically as indicated by the appended claims.

What is claimed as new and useful is:-

1. A brush plate unitary assembly including a relatively rigidinsulating supporting plate for a plurality of brush-holders, and ametal reinforcement for said plate extending about the peripheral edgethereof, said insulating supporting plate being maintainable in fixedposition with respect to a support for said assembly by said metalreinforcement.

2. In a commutator brush rigging, a unitary assembly including aninsulating supporting disk, a reinforcing member secured to andextending about the peripheral edge of said disk, and a secondinsulating disk supported by said reinforcing member in spaced, parallelrelation with respect to said first disk.

3. In a commutator brush rigging a unitary assembly including acentrally apertured relatively rigid plate of insulating materialadapted to support a plurality of brush holders, a plurality of brushholders operatively mounted upon said plate, and metallic means forstrengthening and lending rigidity to said insulating plate, said meansbeing permanently included as a part of said assembly and adapted tosupport the same in fixed position with respect to a support therefor.

4. In a commutator brush rigging, a unitary assembly including acentrally apertured relatively rigid plate of insulating materialadapted to support a plurality of brush holders, a plurality of brushholders operatively mounted upon said plate, and metal reinforcing meanssecured to the marginal edge of said insulating plate, said reinforcingmeans being permanently included as a part of said assembly and providedwith an annular seat for centering the assembly against the commutatorend of a generator housing.

5. In a commutator brush rigging, a unitary assembly including acentrally apertured plate of insulating material adapted to be slippedover a commutator, a metal reinforcing ring permanently secured to themarginal edge of said plate, and a radially extending flange on saidring adapted for accommodation within the commutator end of a generatorhousing whereby to center said plate with respect to the commutator.

6. A commutator brush rigging including a main plate of insulatingmaterial, an auxiliary plate of insulating material, a pair ofcommutator brush sets respectively supported by said plates, and a metalreinforcing ring secured to the peripheral edge of said main plate andprovided with means for supporting said auxiliary plate in axiallyspaced relation with respect to said main plate. I

"I. In a commutator brush rigging, a unitary assembly including arelatively rigid insulating plate adapted to surround the inner end of acommutator and to support a plurality of brush holders, a plurality ofbrush holders supported upon said plate in operative relation withrespect to said commutator, and a metal ring permanently secured to themarginal edge of said insulating plate, said ring serving commonly as areinforcement for the plate and as means for centering the same withinthe commutator end of a generator housing.

8. A commutator brush rigging including a main plate of insulatingmaterial arranged in embracing relation about the inner end of acommutator, a plurality of brush holders supported by said plate inoperative relation with respect to said commutator, a metal reinforcingring secured to the marginal edge of said main plate, said ring beingprovided with a plurality of circumferentially spaced arms axiallyoffset from said main plate, an auxiliary insulating plate supported bysaid arms, said auxiliary plate being disposed substantially in theplane of the inner end of a second commutator arranged in advance ofsaid first commutator, and

a plurality of brush holders supported upon said auxiliary plate inoperative relation with respect to said second commutator.

9. In a commutator brush rigging, in combination, a unitary assemblyincluding a pair of insulating plates arranged in spaced parallelrelation, a metal ring secured to and extending about the peripheraledge of one of said plates and having a plurality of radially inturnedarms to which the other of said plates is secured, two sets of brushholders respectively mounted upon said plates, and means extendingbetween a brush holder of one set and a brush holder of the other set toeffect an electrical connection therebetween.

10. In a brush rigging, in combination, a main plate of insulatingmaterial, a metallic reinforcing ring extending about and secured to theperipheral edge of said plate, a brush holder supported upon said plateby means of one or more tubular rivets, an auxiliary insulating plateadapted to be supported by said ring in spaced parallel relation withrespect to said main plate, a brush holder mounted upon said auxiliaryplate, and a pin projected from said brush holder into the bore of oneof the securing rivets for said first brush holder whereby to effect anelectrical connection between said brush holders. 11. In a brushrigging, in combination, a main plate of insulating material, a metallicreinforcing ring extending about and secured to the peripheral edge ofsaid plate, a brush holder supportedupon said plate by means of one ormore tubular rivets, an auxiliary insulating plate adapted to besupported by said ring in spaced parallel relation with respect to saidmain plate, a brush holder mounted upon said auxiliary plate, and a pinprojected from said brush holder into the bore of one of the securingrivets for said first brush holder whereby to effect an electricalconnection between said brush holders, said electrical connection beingdisruptable upon detaching said auxiliary plate from said ring.

HERBERT J. GRAHAM. LEWIS A. DARLING.

